| //===- X86Relocator.cpp -------------------------------------------===// |
| // |
| // The MCLinker Project |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| #include "X86Relocator.h" |
| #include "X86RelocationFunctions.h" |
| |
| #include <mcld/IRBuilder.h> |
| #include <mcld/LinkerConfig.h> |
| #include <mcld/LD/ELFFileFormat.h> |
| #include <mcld/LD/ELFSegmentFactory.h> |
| #include <mcld/LD/ELFSegment.h> |
| #include <mcld/LD/LDSymbol.h> |
| #include <mcld/Object/ObjectBuilder.h> |
| #include <mcld/Support/MsgHandling.h> |
| |
| #include <llvm/ADT/Twine.h> |
| #include <llvm/Support/DataTypes.h> |
| #include <llvm/Support/ELF.h> |
| |
| namespace mcld { |
| |
| //===--------------------------------------------------------------------===// |
| // X86_32 Relocation helper function |
| //===--------------------------------------------------------------------===// |
| /// helper_DynRel - Get an relocation entry in .rel.dyn |
| static Relocation& helper_DynRel_init(ResolveInfo* pSym, |
| Fragment& pFrag, |
| uint64_t pOffset, |
| Relocator::Type pType, |
| X86_32Relocator& pParent) { |
| X86_32GNULDBackend& ld_backend = pParent.getTarget(); |
| Relocation& rel_entry = *ld_backend.getRelDyn().create(); |
| rel_entry.setType(pType); |
| rel_entry.targetRef().assign(pFrag, pOffset); |
| if (pType == llvm::ELF::R_386_RELATIVE || pSym == NULL) |
| rel_entry.setSymInfo(NULL); |
| else |
| rel_entry.setSymInfo(pSym); |
| |
| return rel_entry; |
| } |
| |
| /// helper_use_relative_reloc - Check if symbol ceuse relocation |
| /// R_386_RELATIVE |
| static bool helper_use_relative_reloc(const ResolveInfo& pSym, |
| const X86_32Relocator& pFactory) { |
| // if symbol is dynamic or undefine or preemptible |
| if (pSym.isDyn() || pSym.isUndef() || |
| pFactory.getTarget().isSymbolPreemptible(pSym)) |
| return false; |
| return true; |
| } |
| |
| static X86_32GOTEntry& helper_GOT_init(Relocation& pReloc, |
| bool pHasRel, |
| X86_32Relocator& pParent) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| X86_32GNULDBackend& ld_backend = pParent.getTarget(); |
| assert(pParent.getSymGOTMap().lookUp(*rsym) == NULL); |
| |
| X86_32GOTEntry* got_entry = ld_backend.getGOT().create(); |
| pParent.getSymGOTMap().record(*rsym, *got_entry); |
| |
| if (!pHasRel) { |
| // No corresponding dynamic relocation, initialize to the symbol value. |
| got_entry->setValue(X86Relocator::SymVal); |
| } else { |
| // Initialize got_entry content and the corresponding dynamic relocation. |
| if (helper_use_relative_reloc(*rsym, pParent)) { |
| helper_DynRel_init( |
| rsym, *got_entry, 0x0, llvm::ELF::R_386_RELATIVE, pParent); |
| got_entry->setValue(X86Relocator::SymVal); |
| } else { |
| helper_DynRel_init( |
| rsym, *got_entry, 0x0, llvm::ELF::R_386_GLOB_DAT, pParent); |
| got_entry->setValue(0x0); |
| } |
| } |
| return *got_entry; |
| } |
| |
| static Relocator::Address helper_GOT_ORG(X86_32Relocator& pParent) { |
| return pParent.getTarget().getGOTPLT().addr(); |
| } |
| |
| static Relocator::Address helper_get_GOT_address(Relocation& pReloc, |
| X86_32Relocator& pParent) { |
| X86_32GOTEntry* got_entry = pParent.getSymGOTMap().lookUp(*pReloc.symInfo()); |
| assert(got_entry != NULL); |
| return pParent.getTarget().getGOT().addr() + got_entry->getOffset(); |
| } |
| |
| static PLTEntryBase& helper_PLT_init(Relocation& pReloc, |
| X86_32Relocator& pParent) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| X86_32GNULDBackend& ld_backend = pParent.getTarget(); |
| assert(pParent.getSymPLTMap().lookUp(*rsym) == NULL); |
| |
| PLTEntryBase* plt_entry = ld_backend.getPLT().create(); |
| pParent.getSymPLTMap().record(*rsym, *plt_entry); |
| |
| // initialize plt and the corresponding gotplt and dyn rel entry. |
| assert(pParent.getSymGOTPLTMap().lookUp(*rsym) == NULL && |
| "PLT entry not exist, but GOTPLT entry exist!"); |
| X86_32GOTEntry* gotplt_entry = ld_backend.getGOTPLT().create(); |
| pParent.getSymGOTPLTMap().record(*rsym, *gotplt_entry); |
| |
| // init the corresponding rel entry in .rel.plt |
| Relocation& rel_entry = *ld_backend.getRelPLT().create(); |
| rel_entry.setType(llvm::ELF::R_386_JUMP_SLOT); |
| rel_entry.targetRef().assign(*gotplt_entry); |
| rel_entry.setSymInfo(rsym); |
| return *plt_entry; |
| } |
| |
| static Relocator::Address helper_get_PLT_address(ResolveInfo& pSym, |
| X86_32Relocator& pParent) { |
| PLTEntryBase* plt_entry = pParent.getSymPLTMap().lookUp(pSym); |
| assert(plt_entry != NULL); |
| return pParent.getTarget().getPLT().addr() + plt_entry->getOffset(); |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // X86_32 Relocation Functions and Tables |
| //===--------------------------------------------------------------------===// |
| DECL_X86_32_APPLY_RELOC_FUNCS |
| |
| /// the prototype of applying function |
| typedef Relocator::Result (*X86_32ApplyFunctionType)(Relocation& pReloc, |
| X86_32Relocator& pParent); |
| |
| // the table entry of applying functions |
| struct X86_32ApplyFunctionTriple { |
| X86_32ApplyFunctionType func; |
| unsigned int type; |
| const char* name; |
| unsigned int size; |
| }; |
| |
| // declare the table of applying functions |
| static const X86_32ApplyFunctionTriple X86_32ApplyFunctions[] = { |
| DECL_X86_32_APPLY_RELOC_FUNC_PTRS}; |
| |
| //===--------------------------------------------------------------------===// |
| // X86Relocator |
| //===--------------------------------------------------------------------===// |
| X86Relocator::X86Relocator(const LinkerConfig& pConfig) : Relocator(pConfig) { |
| } |
| |
| X86Relocator::~X86Relocator() { |
| } |
| |
| void X86Relocator::scanRelocation(Relocation& pReloc, |
| IRBuilder& pLinker, |
| Module& pModule, |
| LDSection& pSection, |
| Input& pInput) { |
| if (LinkerConfig::Object == config().codeGenType()) |
| return; |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| assert(rsym != NULL && |
| "ResolveInfo of relocation not set while scanRelocation"); |
| |
| assert(pSection.getLink() != NULL); |
| if ((pSection.getLink()->flag() & llvm::ELF::SHF_ALLOC) == 0) |
| return; |
| |
| // Scan relocation type to determine if the GOT/PLT/Dynamic Relocation |
| // entries should be created. |
| if (rsym->isLocal()) // rsym is local |
| scanLocalReloc(pReloc, pLinker, pModule, pSection); |
| else // rsym is external |
| scanGlobalReloc(pReloc, pLinker, pModule, pSection); |
| |
| // check if we should issue undefined reference for the relocation target |
| // symbol |
| if (rsym->isUndef() && !rsym->isDyn() && !rsym->isWeak() && !rsym->isNull()) |
| issueUndefRef(pReloc, pSection, pInput); |
| } |
| |
| void X86Relocator::addCopyReloc(ResolveInfo& pSym, X86GNULDBackend& pTarget) { |
| Relocation& rel_entry = *pTarget.getRelDyn().create(); |
| rel_entry.setType(pTarget.getCopyRelType()); |
| assert(pSym.outSymbol()->hasFragRef()); |
| rel_entry.targetRef().assign(*pSym.outSymbol()->fragRef()); |
| rel_entry.setSymInfo(&pSym); |
| } |
| |
| /// defineSymbolforCopyReloc |
| /// For a symbol needing copy relocation, define a copy symbol in the BSS |
| /// section and all other reference to this symbol should refer to this |
| /// copy. |
| /// @note This is executed at `scan relocation' stage. |
| LDSymbol& X86Relocator::defineSymbolforCopyReloc(IRBuilder& pBuilder, |
| const ResolveInfo& pSym, |
| X86GNULDBackend& pTarget) { |
| // get or create corresponding BSS LDSection |
| LDSection* bss_sect_hdr = NULL; |
| ELFFileFormat* file_format = pTarget.getOutputFormat(); |
| if (ResolveInfo::ThreadLocal == pSym.type()) |
| bss_sect_hdr = &file_format->getTBSS(); |
| else |
| bss_sect_hdr = &file_format->getBSS(); |
| |
| // get or create corresponding BSS SectionData |
| assert(bss_sect_hdr != NULL); |
| SectionData* bss_section = NULL; |
| if (bss_sect_hdr->hasSectionData()) |
| bss_section = bss_sect_hdr->getSectionData(); |
| else |
| bss_section = IRBuilder::CreateSectionData(*bss_sect_hdr); |
| |
| // Determine the alignment by the symbol value |
| // FIXME: here we use the largest alignment |
| uint32_t addralign = config().targets().bitclass() / 8; |
| |
| // allocate space in BSS for the copy symbol |
| Fragment* frag = new FillFragment(0x0, 1, pSym.size()); |
| uint64_t size = ObjectBuilder::AppendFragment(*frag, *bss_section, addralign); |
| bss_sect_hdr->setSize(bss_sect_hdr->size() + size); |
| |
| // change symbol binding to Global if it's a weak symbol |
| ResolveInfo::Binding binding = (ResolveInfo::Binding)pSym.binding(); |
| if (binding == ResolveInfo::Weak) |
| binding = ResolveInfo::Global; |
| |
| // Define the copy symbol in the bss section and resolve it |
| LDSymbol* cpy_sym = pBuilder.AddSymbol<IRBuilder::Force, IRBuilder::Resolve>( |
| pSym.name(), |
| (ResolveInfo::Type)pSym.type(), |
| ResolveInfo::Define, |
| binding, |
| pSym.size(), // size |
| 0x0, // value |
| FragmentRef::Create(*frag, 0x0), |
| (ResolveInfo::Visibility)pSym.other()); |
| |
| // output all other alias symbols if any |
| Module& pModule = pBuilder.getModule(); |
| Module::AliasList* alias_list = pModule.getAliasList(pSym); |
| if (alias_list != NULL) { |
| Module::alias_iterator it, it_e = alias_list->end(); |
| for (it = alias_list->begin(); it != it_e; ++it) { |
| const ResolveInfo* alias = *it; |
| if (alias != &pSym && alias->isDyn()) { |
| pBuilder.AddSymbol<IRBuilder::Force, IRBuilder::Resolve>( |
| alias->name(), |
| (ResolveInfo::Type)alias->type(), |
| ResolveInfo::Define, |
| binding, |
| alias->size(), // size |
| 0x0, // value |
| FragmentRef::Create(*frag, 0x0), |
| (ResolveInfo::Visibility)alias->other()); |
| } |
| } |
| } |
| |
| return *cpy_sym; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // X86_32Relocator |
| //===----------------------------------------------------------------------===// |
| X86_32Relocator::X86_32Relocator(X86_32GNULDBackend& pParent, |
| const LinkerConfig& pConfig) |
| : X86Relocator(pConfig), m_Target(pParent) { |
| } |
| |
| Relocator::Result X86_32Relocator::applyRelocation(Relocation& pRelocation) { |
| Relocation::Type type = pRelocation.type(); |
| |
| if (type >= sizeof(X86_32ApplyFunctions) / sizeof(X86_32ApplyFunctions[0])) { |
| return Unknown; |
| } |
| |
| // apply the relocation |
| return X86_32ApplyFunctions[type].func(pRelocation, *this); |
| } |
| |
| const char* X86_32Relocator::getName(Relocation::Type pType) const { |
| return X86_32ApplyFunctions[pType].name; |
| } |
| |
| Relocator::Size X86_32Relocator::getSize(Relocation::Type pType) const { |
| return X86_32ApplyFunctions[pType].size; |
| } |
| |
| bool X86_32Relocator::mayHaveFunctionPointerAccess( |
| const Relocation& pReloc) const { |
| switch (pReloc.type()) { |
| case llvm::ELF::R_386_32: |
| case llvm::ELF::R_386_16: |
| case llvm::ELF::R_386_8: |
| case llvm::ELF::R_386_GOTOFF: |
| case llvm::ELF::R_386_GOT32: { |
| return true; |
| } |
| default: { return false; } |
| } |
| } |
| |
| void X86_32Relocator::scanLocalReloc(Relocation& pReloc, |
| IRBuilder& pBuilder, |
| Module& pModule, |
| LDSection& pSection) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| |
| switch (pReloc.type()) { |
| case llvm::ELF::R_386_32: |
| // If buiding PIC object (shared library or PIC executable), |
| // a dynamic relocations with RELATIVE type to this location is needed. |
| // Reserve an entry in .rel.dyn |
| if (config().isCodeIndep()) { |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| // set up the dyn rel directly |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_386_RELATIVE, |
| *this); |
| } |
| return; |
| |
| case llvm::ELF::R_386_16: |
| case llvm::ELF::R_386_8: |
| // If buiding PIC object (shared library or PIC executable), |
| // a dynamic relocations with RELATIVE type to this location is needed. |
| // Reserve an entry in .rel.dyn |
| if (config().isCodeIndep()) { |
| // set up the dyn rel directly |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| pReloc.type(), |
| *this); |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| } |
| return; |
| |
| case llvm::ELF::R_386_PLT32: |
| return; |
| |
| case llvm::ELF::R_386_GOTOFF: |
| case llvm::ELF::R_386_GOTPC: |
| // FIXME: A GOT section is needed |
| return; |
| |
| case llvm::ELF::R_386_GOT32: |
| // Symbol needs GOT entry, reserve entry in .got |
| // return if we already create GOT for this symbol |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| |
| // FIXME: check STT_GNU_IFUNC symbol |
| |
| // If building PIC object, a dynamic relocation with |
| // type RELATIVE is needed to relocate this GOT entry. |
| if (config().isCodeIndep()) |
| helper_GOT_init(pReloc, true, *this); |
| else |
| helper_GOT_init(pReloc, false, *this); |
| |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| |
| case llvm::ELF::R_386_PC32: |
| case llvm::ELF::R_386_PC16: |
| case llvm::ELF::R_386_PC8: |
| return; |
| |
| case llvm::ELF::R_386_TLS_GD: { |
| // FIXME: no linker optimization for TLS relocation |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| |
| // define the section symbol for .tdata or .tbss |
| // the target symbol of the created dynamic relocation should be the |
| // section symbol of the section which this symbol defined. so we |
| // need to define that section symbol here |
| ELFFileFormat* file_format = getTarget().getOutputFormat(); |
| const LDSection* sym_sect = |
| &rsym->outSymbol()->fragRef()->frag()->getParent()->getSection(); |
| LDSymbol* sect_sym = NULL; |
| if (&file_format->getTData() == sym_sect) { |
| if (!getTarget().hasTDATASymbol()) { |
| sect_sym = pModule.getSectionSymbolSet().get(*sym_sect); |
| getTarget().setTDATASymbol(*sect_sym); |
| } |
| } else if (&file_format->getTBSS() == sym_sect || rsym->isCommon()) { |
| if (!getTarget().hasTBSSSymbol()) { |
| sect_sym = pModule.getSectionSymbolSet().get(*sym_sect); |
| getTarget().setTBSSSymbol(*sect_sym); |
| } |
| } else { |
| error(diag::invalid_tls) << rsym->name() << sym_sect->name(); |
| } |
| |
| // set up a pair of got entries and a dyn rel |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| X86_32GOTEntry* got_entry1 = getTarget().getGOT().create(); |
| X86_32GOTEntry* got_entry2 = getTarget().getGOT().create(); |
| getSymGOTMap().record(*rsym, *got_entry1, *got_entry2); |
| // set up value of got entries, the value of got_entry2 should be the |
| // symbol value, which has to be set during apply relocation |
| got_entry1->setValue(0x0); |
| |
| // setup dyn rel for got_entry1 |
| Relocation& rel_entry1 = helper_DynRel_init( |
| rsym, *got_entry1, 0x0, llvm::ELF::R_386_TLS_DTPMOD32, *this); |
| // for local tls symbol, add rel entry against the section symbol this |
| // symbol belong to (.tdata or .tbss) |
| rel_entry1.setSymInfo(sect_sym->resolveInfo()); |
| return; |
| } |
| case llvm::ELF::R_386_TLS_LDM: |
| getTLSModuleID(); |
| return; |
| |
| case llvm::ELF::R_386_TLS_LDO_32: |
| return; |
| |
| case llvm::ELF::R_386_TLS_IE: { |
| getTarget().setHasStaticTLS(); |
| |
| // if building shared object, a RELATIVE dynamic relocation is needed |
| if (LinkerConfig::DynObj == config().codeGenType()) { |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_386_RELATIVE, |
| *this); |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| } else { |
| // for local sym, we can convert ie to le if not building shared object |
| convertTLSIEtoLE(pReloc, pSection); |
| return; |
| } |
| |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| |
| // set up the got and the corresponding rel entry |
| X86_32GOTEntry* got_entry = getTarget().getGOT().create(); |
| getSymGOTMap().record(*rsym, *got_entry); |
| got_entry->setValue(0x0); |
| helper_DynRel_init( |
| rsym, *got_entry, 0x0, llvm::ELF::R_386_TLS_TPOFF, *this); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| // add symbol to dyn sym table |
| getTarget().getRelDyn().addSymbolToDynSym(*rsym->outSymbol()); |
| return; |
| } |
| |
| case llvm::ELF::R_386_TLS_GOTIE: { |
| getTarget().setHasStaticTLS(); |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| // set up the got and the corresponding dyn rel |
| X86_32GOTEntry* got_entry = getTarget().getGOT().create(); |
| getSymGOTMap().record(*rsym, *got_entry); |
| got_entry->setValue(0x0); |
| helper_DynRel_init( |
| rsym, *got_entry, 0x0, llvm::ELF::R_386_TLS_TPOFF, *this); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| getTarget().getRelDyn().addSymbolToDynSym(*rsym->outSymbol()); |
| return; |
| } |
| |
| case llvm::ELF::R_386_TLS_LE: |
| case llvm::ELF::R_386_TLS_LE_32: |
| getTarget().setHasStaticTLS(); |
| // if buildint shared object, a dynamic relocation is needed |
| if (LinkerConfig::DynObj == config().codeGenType()) { |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_386_TLS_TPOFF, |
| *this); |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| // the target symbol of the dynamic relocation is rsym, so we need to |
| // emit it into .dynsym |
| assert(rsym->outSymbol() != NULL); |
| getTarget().getRelDyn().addSymbolToDynSym(*rsym->outSymbol()); |
| } |
| return; |
| |
| default: |
| fatal(diag::unsupported_relocation) << static_cast<int>(pReloc.type()) |
| << "mclinker@googlegroups.com"; |
| break; |
| } // end switch |
| } |
| |
| void X86_32Relocator::scanGlobalReloc(Relocation& pReloc, |
| IRBuilder& pBuilder, |
| Module& pModule, |
| LDSection& pSection) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| |
| switch (pReloc.type()) { |
| case llvm::ELF::R_386_32: |
| case llvm::ELF::R_386_16: |
| case llvm::ELF::R_386_8: |
| // Absolute relocation type, symbol may needs PLT entry or |
| // dynamic relocation entry |
| if (getTarget().symbolNeedsPLT(*rsym)) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)) { |
| // Symbol needs PLT entry, we need a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| |
| if (getTarget() |
| .symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & ReservePLT), true)) { |
| // symbol needs dynamic relocation entry, set up the dynrel entry |
| if (getTarget().symbolNeedsCopyReloc(pReloc, *rsym)) { |
| LDSymbol& cpy_sym = |
| defineSymbolforCopyReloc(pBuilder, *rsym, getTarget()); |
| addCopyReloc(*cpy_sym.resolveInfo(), getTarget()); |
| } else { |
| // set Rel bit and the dyn rel |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| if (llvm::ELF::R_386_32 == pReloc.type() && |
| helper_use_relative_reloc(*rsym, *this)) { |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_386_RELATIVE, |
| *this); |
| } else { |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| pReloc.type(), |
| *this); |
| } |
| } |
| } |
| return; |
| |
| case llvm::ELF::R_386_GOTOFF: |
| case llvm::ELF::R_386_GOTPC: { |
| // FIXME: A GOT section is needed |
| return; |
| } |
| |
| case llvm::ELF::R_386_PLT32: |
| // A PLT entry is needed when building shared library |
| |
| // return if we already create plt for this symbol |
| if (rsym->reserved() & ReservePLT) |
| return; |
| |
| // if the symbol's value can be decided at link time, then no need plt |
| if (getTarget().symbolFinalValueIsKnown(*rsym)) |
| return; |
| |
| // if symbol is defined in the ouput file and it's not |
| // preemptible, no need plt |
| if (rsym->isDefine() && !rsym->isDyn() && |
| !getTarget().isSymbolPreemptible(*rsym)) |
| return; |
| |
| // Symbol needs PLT entry, we need a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| return; |
| |
| case llvm::ELF::R_386_GOT32: |
| // Symbol needs GOT entry, reserve entry in .got |
| // return if we already create GOT for this symbol |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| // if the symbol cannot be fully resolved at link time, then we need a |
| // dynamic relocation |
| if (!getTarget().symbolFinalValueIsKnown(*rsym)) |
| helper_GOT_init(pReloc, true, *this); |
| else |
| helper_GOT_init(pReloc, false, *this); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| |
| case llvm::ELF::R_386_PC32: |
| case llvm::ELF::R_386_PC16: |
| case llvm::ELF::R_386_PC8: |
| |
| if (getTarget().symbolNeedsPLT(*rsym) && |
| LinkerConfig::DynObj != config().codeGenType()) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)) { |
| // Symbol needs PLT entry, we need a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. |
| // set PLT bit |
| helper_PLT_init(pReloc, *this); |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| |
| if (getTarget() |
| .symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & ReservePLT), false)) { |
| // symbol needs dynamic relocation entry, setup an entry in .rel.dyn |
| if (getTarget().symbolNeedsCopyReloc(pReloc, *rsym)) { |
| LDSymbol& cpy_sym = |
| defineSymbolforCopyReloc(pBuilder, *rsym, getTarget()); |
| addCopyReloc(*cpy_sym.resolveInfo(), getTarget()); |
| } else { |
| // set Rel bit and the dyn rel |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| if (llvm::ELF::R_386_32 == pReloc.type() && |
| helper_use_relative_reloc(*rsym, *this)) { |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_386_RELATIVE, |
| *this); |
| } else { |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| pReloc.type(), |
| *this); |
| } |
| } |
| } |
| return; |
| |
| case llvm::ELF::R_386_TLS_GD: { |
| // FIXME: no linker optimization for TLS relocation |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| |
| // set up a pair of got entries and a pair of dyn rel |
| X86_32GOTEntry* got_entry1 = getTarget().getGOT().create(); |
| X86_32GOTEntry* got_entry2 = getTarget().getGOT().create(); |
| getSymGOTMap().record(*rsym, *got_entry1, *got_entry2); |
| got_entry1->setValue(0x0); |
| got_entry2->setValue(0x0); |
| // setup dyn rel for got entries against rsym |
| helper_DynRel_init( |
| rsym, *got_entry1, 0x0, llvm::ELF::R_386_TLS_DTPMOD32, *this); |
| helper_DynRel_init( |
| rsym, *got_entry2, 0x0, llvm::ELF::R_386_TLS_DTPOFF32, *this); |
| |
| // add the rsym to dynamic symbol table |
| getTarget().getRelDyn().addSymbolToDynSym(*rsym->outSymbol()); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| } |
| |
| case llvm::ELF::R_386_TLS_LDM: |
| getTLSModuleID(); |
| return; |
| |
| case llvm::ELF::R_386_TLS_LDO_32: |
| return; |
| |
| case llvm::ELF::R_386_TLS_IE: { |
| getTarget().setHasStaticTLS(); |
| // if buildint shared object, a RELATIVE dynamic relocation is needed |
| if (LinkerConfig::DynObj == config().codeGenType()) { |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_386_RELATIVE, |
| *this); |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| } else { |
| // for global sym, we can convert ie to le if its final value is known |
| if (getTarget().symbolFinalValueIsKnown(*rsym)) { |
| convertTLSIEtoLE(pReloc, pSection); |
| return; |
| } |
| } |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| // set up the got and the corresponding rel entry |
| X86_32GOTEntry* got_entry = getTarget().getGOT().create(); |
| getSymGOTMap().record(*rsym, *got_entry); |
| got_entry->setValue(0x0); |
| helper_DynRel_init( |
| rsym, *got_entry, 0x0, llvm::ELF::R_386_TLS_TPOFF, *this); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| } |
| |
| case llvm::ELF::R_386_TLS_GOTIE: { |
| getTarget().setHasStaticTLS(); |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| // set up the got and the corresponding dyn rel |
| X86_32GOTEntry* got_entry = getTarget().getGOT().create(); |
| getSymGOTMap().record(*rsym, *got_entry); |
| got_entry->setValue(0x0); |
| helper_DynRel_init( |
| rsym, *got_entry, 0x0, llvm::ELF::R_386_TLS_TPOFF, *this); |
| getTarget().getRelDyn().addSymbolToDynSym(*rsym->outSymbol()); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| } |
| |
| case llvm::ELF::R_386_TLS_LE: |
| case llvm::ELF::R_386_TLS_LE_32: |
| getTarget().setHasStaticTLS(); |
| // if buildint shared object, a dynamic relocation is needed |
| if (LinkerConfig::DynObj == config().codeGenType()) { |
| helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_386_TLS_TPOFF, |
| *this); |
| getTarget().getRelDyn().addSymbolToDynSym(*rsym->outSymbol()); |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| } |
| return; |
| |
| default: { |
| fatal(diag::unsupported_relocation) << static_cast<int>(pReloc.type()) |
| << "mclinker@googlegroups.com"; |
| break; |
| } |
| } // end switch |
| } |
| |
| // Create a GOT entry for the TLS module index |
| X86_32GOTEntry& X86_32Relocator::getTLSModuleID() { |
| static X86_32GOTEntry* got_entry = NULL; |
| if (got_entry != NULL) |
| return *got_entry; |
| |
| // Allocate 2 got entries and 1 dynamic reloc for R_386_TLS_LDM |
| got_entry = getTarget().getGOT().create(); |
| getTarget().getGOT().create()->setValue(0x0); |
| |
| helper_DynRel_init( |
| NULL, *got_entry, 0x0, llvm::ELF::R_386_TLS_DTPMOD32, *this); |
| return *got_entry; |
| } |
| |
| /// convert R_386_TLS_IE to R_386_TLS_LE |
| void X86_32Relocator::convertTLSIEtoLE(Relocation& pReloc, |
| LDSection& pSection) { |
| assert(pReloc.type() == llvm::ELF::R_386_TLS_IE); |
| assert(pReloc.targetRef().frag() != NULL); |
| |
| // 1. create the new relocs |
| Relocation* reloc = |
| Relocation::Create(X86_32Relocator::R_386_TLS_OPT, |
| *FragmentRef::Create(*pReloc.targetRef().frag(), |
| pReloc.targetRef().offset() - 1), |
| 0x0); |
| // FIXME: should we create a special symbol for the tls opt instead? |
| reloc->setSymInfo(pReloc.symInfo()); |
| |
| // 2. modify the opcodes to the appropriate ones |
| uint8_t* op = (reinterpret_cast<uint8_t*>(&reloc->target())); |
| if (op[0] == 0xa1) { |
| op[0] = 0xb8; |
| } else { |
| // create the new reloc (move 1 byte forward). |
| reloc = Relocation::Create( |
| X86_32Relocator::R_386_TLS_OPT, |
| *FragmentRef::Create(*pReloc.targetRef().frag(), |
| pReloc.targetRef().offset() - 2), |
| 0x0); |
| reloc->setSymInfo(pReloc.symInfo()); |
| op = (reinterpret_cast<uint8_t*>(&reloc->target())); |
| switch (op[0]) { |
| case 0x8b: |
| assert((op[1] & 0xc7) == 0x05); |
| op[0] = 0xc7; |
| op[1] = 0xc0 | ((op[1] >> 3) & 7); |
| break; |
| case 0x03: |
| assert((op[1] & 0xc7) == 0x05); |
| op[0] = 0x81; |
| op[1] = 0xc0 | ((op[1] >> 3) & 7); |
| break; |
| default: |
| assert(0); |
| break; |
| } |
| } |
| |
| // 3. insert the new relocs "BEFORE" the original reloc. |
| assert(reloc != NULL); |
| pSection.getRelocData()->getRelocationList().insert( |
| RelocData::iterator(pReloc), reloc); |
| |
| // 4. change the type of the original reloc |
| pReloc.setType(llvm::ELF::R_386_TLS_LE); |
| } |
| |
| uint32_t X86_32Relocator::getDebugStringOffset(Relocation& pReloc) const { |
| if (pReloc.type() != llvm::ELF::R_386_32) |
| error(diag::unsupport_reloc_for_debug_string) |
| << getName(pReloc.type()) << "mclinker@googlegroups.com"; |
| |
| if (pReloc.symInfo()->type() == ResolveInfo::Section) |
| return pReloc.target(); |
| else |
| return pReloc.symInfo()->outSymbol()->fragRef()->offset() + |
| pReloc.target() + pReloc.addend(); |
| } |
| |
| void X86_32Relocator::applyDebugStringOffset(Relocation& pReloc, |
| uint32_t pOffset) { |
| pReloc.target() = pOffset; |
| } |
| |
| //================================================// |
| // X86_32 Each relocation function implementation // |
| //================================================// |
| |
| // R_386_NONE |
| Relocator::Result none(Relocation& pReloc, X86_32Relocator& pParent) { |
| return Relocator::OK; |
| } |
| |
| // R_386_32: S + A |
| // R_386_16 |
| // R_386_8 |
| Relocator::Result abs(Relocation& pReloc, X86_32Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::DWord S = pReloc.symValue(); |
| bool has_dyn_rel = pParent.getTarget().symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & X86Relocator::ReservePLT), true); |
| |
| LDSection& target_sect = pReloc.targetRef().frag()->getParent()->getSection(); |
| // If the flag of target section is not ALLOC, we will not scan this |
| // relocation but perform static relocation. (e.g., applying .debug section) |
| if ((llvm::ELF::SHF_ALLOC & target_sect.flag()) == 0x0) { |
| pReloc.target() = S + A; |
| return Relocator::OK; |
| } |
| |
| // An external symbol may need PLT and dynamic relocation |
| if (!rsym->isLocal()) { |
| if (rsym->reserved() & X86Relocator::ReservePLT) { |
| S = helper_get_PLT_address(*rsym, pParent); |
| } |
| // If we generate a dynamic relocation (except R_386_RELATIVE) |
| // for a place, we should not perform static relocation on it |
| // in order to keep the addend store in the place correct. |
| if (has_dyn_rel) |
| if (llvm::ELF::R_386_32 != pReloc.type() || |
| (!helper_use_relative_reloc(*rsym, pParent))) |
| return Relocator::OK; |
| } |
| |
| // perform static relocation |
| pReloc.target() = S + A; |
| return Relocator::OK; |
| } |
| |
| // R_386_PC32: S + A - P |
| // R_386_PC16 |
| // R_386_PC8 |
| Relocator::Result rel(Relocation& pReloc, X86_32Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::DWord S = pReloc.symValue(); |
| Relocator::DWord P = pReloc.place(); |
| bool has_dyn_rel = pParent.getTarget().symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & X86Relocator::ReservePLT), true); |
| |
| LDSection& target_sect = pReloc.targetRef().frag()->getParent()->getSection(); |
| // If the flag of target section is not ALLOC, we will not scan this |
| // relocation |
| // but perform static relocation. (e.g., applying .debug section) |
| if ((llvm::ELF::SHF_ALLOC & target_sect.flag()) == 0x0) { |
| pReloc.target() = S + A - P; |
| return Relocator::OK; |
| } |
| |
| // An external symbol may need PLT and dynamic relocation |
| if (!rsym->isLocal()) { |
| if (rsym->reserved() & X86Relocator::ReservePLT) { |
| S = helper_get_PLT_address(*rsym, pParent); |
| pReloc.target() = S + A - P; |
| } |
| if (has_dyn_rel) |
| if (!helper_use_relative_reloc(*rsym, pParent)) |
| return Relocator::OK; |
| } |
| |
| // perform static relocation |
| pReloc.target() = S + A - P; |
| return Relocator::OK; |
| } |
| |
| // R_386_GOTOFF: S + A - GOT_ORG |
| Relocator::Result gotoff32(Relocation& pReloc, X86_32Relocator& pParent) { |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::Address GOT_ORG = helper_GOT_ORG(pParent); |
| Relocator::Address S = pReloc.symValue(); |
| |
| pReloc.target() = S + A - GOT_ORG; |
| return Relocator::OK; |
| } |
| |
| // R_386_GOTPC: GOT_ORG + A - P |
| Relocator::Result gotpc32(Relocation& pReloc, X86_32Relocator& pParent) { |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::Address GOT_ORG = helper_GOT_ORG(pParent); |
| // Apply relocation. |
| pReloc.target() = GOT_ORG + A - pReloc.place(); |
| return Relocator::OK; |
| } |
| |
| // R_386_GOT32: GOT(S) + A - GOT_ORG |
| Relocator::Result got32(Relocation& pReloc, X86_32Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| if (!(rsym->reserved() & (X86Relocator::ReserveGOT))) |
| return Relocator::BadReloc; |
| |
| // set up got entry value if the got has no dyn rel or |
| // the dyn rel is RELATIVE |
| X86_32GOTEntry* got_entry = pParent.getSymGOTMap().lookUp(*pReloc.symInfo()); |
| assert(got_entry != NULL); |
| if (got_entry->getValue() == X86Relocator::SymVal) |
| got_entry->setValue(pReloc.symValue()); |
| |
| Relocator::Address GOT_S = helper_get_GOT_address(pReloc, pParent); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::Address GOT_ORG = helper_GOT_ORG(pParent); |
| // Apply relocation. |
| pReloc.target() = GOT_S + A - GOT_ORG; |
| return Relocator::OK; |
| } |
| |
| // R_386_PLT32: PLT(S) + A - P |
| Relocator::Result plt32(Relocation& pReloc, X86_32Relocator& pParent) { |
| // PLT_S depends on if there is a PLT entry. |
| Relocator::Address PLT_S; |
| if ((pReloc.symInfo()->reserved() & X86Relocator::ReservePLT)) |
| PLT_S = helper_get_PLT_address(*pReloc.symInfo(), pParent); |
| else |
| PLT_S = pReloc.symValue(); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::Address P = pReloc.place(); |
| pReloc.target() = PLT_S + A - P; |
| return Relocator::OK; |
| } |
| |
| // R_386_TLS_GD: |
| Relocator::Result tls_gd(Relocation& pReloc, X86_32Relocator& pParent) { |
| // global-dynamic |
| ResolveInfo* rsym = pReloc.symInfo(); |
| // must reserve two pairs of got and dynamic relocation |
| if (!(rsym->reserved() & X86Relocator::ReserveGOT)) |
| return Relocator::BadReloc; |
| |
| ELFFileFormat* file_format = pParent.getTarget().getOutputFormat(); |
| // setup corresponding got and dynamic relocatio entries: |
| // get first got entry, if there is already a got entry for rsym, then apply |
| // this relocation to the got entry directly. If not, setup the corresponding |
| // got and dyn relocation entries |
| X86_32GOTEntry* got_entry1 = pParent.getSymGOTMap().lookUpFirstEntry(*rsym); |
| |
| // set the got_entry2 value to symbol value |
| if (rsym->isLocal()) |
| pParent.getSymGOTMap().lookUpSecondEntry(*rsym)->setValue( |
| pReloc.symValue()); |
| |
| // perform relocation to the first got entry |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| // GOT_OFF - the offset between the got_entry1 and _GLOBAL_OFFSET_TABLE (the |
| // .got.plt section) |
| Relocator::Address GOT_OFF = file_format->getGOT().addr() + |
| got_entry1->getOffset() - |
| file_format->getGOTPLT().addr(); |
| pReloc.target() = GOT_OFF + A; |
| return Relocator::OK; |
| } |
| |
| // R_386_TLS_LDM |
| Relocator::Result tls_ldm(Relocation& pReloc, X86_32Relocator& pParent) { |
| // FIXME: no linker optimization for TLS relocation |
| const X86_32GOTEntry& got_entry = pParent.getTLSModuleID(); |
| |
| // All GOT offsets are relative to the end of the GOT. |
| X86Relocator::SWord GOT_S = |
| got_entry.getOffset() - (pParent.getTarget().getGOTPLT().addr() - |
| pParent.getTarget().getGOT().addr()); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| pReloc.target() = GOT_S + A; |
| |
| return Relocator::OK; |
| } |
| |
| // R_386_TLS_LDO_32 |
| Relocator::Result tls_ldo_32(Relocation& pReloc, X86_32Relocator& pParent) { |
| // FIXME: no linker optimization for TLS relocation |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::Address S = pReloc.symValue(); |
| pReloc.target() = S + A; |
| return Relocator::OK; |
| } |
| |
| // R_X86_TLS_IE |
| Relocator::Result tls_ie(Relocation& pReloc, X86_32Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| if (!(rsym->reserved() & X86Relocator::ReserveGOT)) { |
| return Relocator::BadReloc; |
| } |
| |
| // set up the got and dynamic relocation entries if not exist |
| X86_32GOTEntry* got_entry = pParent.getSymGOTMap().lookUp(*rsym); |
| assert(got_entry != NULL); |
| // perform relocation to the absolute address of got_entry |
| Relocator::Address GOT_S = |
| pParent.getTarget().getGOT().addr() + got_entry->getOffset(); |
| |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| pReloc.target() = GOT_S + A; |
| |
| return Relocator::OK; |
| } |
| |
| // R_386_TLS_GOTIE |
| Relocator::Result tls_gotie(Relocation& pReloc, X86_32Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| if (!(rsym->reserved() & X86Relocator::ReserveGOT)) { |
| return Relocator::BadReloc; |
| } |
| |
| // set up the got and dynamic relocation entries if not exist |
| X86_32GOTEntry* got_entry = pParent.getSymGOTMap().lookUp(*rsym); |
| assert(got_entry != NULL); |
| |
| // All GOT offsets are relative to the end of the GOT. |
| X86Relocator::SWord GOT_S = |
| got_entry->getOffset() - (pParent.getTarget().getGOTPLT().addr() - |
| pParent.getTarget().getGOT().addr()); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| pReloc.target() = GOT_S + A; |
| |
| return Relocator::OK; |
| } |
| |
| // R_X86_TLS_LE |
| Relocator::Result tls_le(Relocation& pReloc, X86_32Relocator& pParent) { |
| if (pReloc.symInfo()->reserved() & X86Relocator::ReserveRel) |
| return Relocator::OK; |
| |
| // perform static relocation |
| // get TLS segment |
| ELFSegmentFactory::const_iterator tls_seg = |
| pParent.getTarget().elfSegmentTable().find( |
| llvm::ELF::PT_TLS, llvm::ELF::PF_R, 0x0); |
| assert(tls_seg != pParent.getTarget().elfSegmentTable().end()); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::Address S = pReloc.symValue(); |
| pReloc.target() = S + A - (*tls_seg)->memsz(); |
| return Relocator::OK; |
| } |
| |
| Relocator::Result unsupported(Relocation& pReloc, X86_32Relocator& pParent) { |
| return Relocator::Unsupported; |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // X86_64 Relocation helper function |
| //===--------------------------------------------------------------------===// |
| /// helper_DynRel - Get an relocation entry in .rela.dyn |
| static Relocation& helper_DynRel_init(ResolveInfo* pSym, |
| Fragment& pFrag, |
| uint64_t pOffset, |
| Relocator::Type pType, |
| X86_64Relocator& pParent) { |
| X86_64GNULDBackend& ld_backend = pParent.getTarget(); |
| Relocation& rel_entry = *ld_backend.getRelDyn().create(); |
| rel_entry.setType(pType); |
| rel_entry.targetRef().assign(pFrag, pOffset); |
| if (pType == llvm::ELF::R_X86_64_RELATIVE || pSym == NULL) |
| rel_entry.setSymInfo(NULL); |
| else |
| rel_entry.setSymInfo(pSym); |
| |
| return rel_entry; |
| } |
| |
| /// helper_use_relative_reloc - Check if symbol can use relocation |
| /// R_X86_64_RELATIVE |
| static bool helper_use_relative_reloc(const ResolveInfo& pSym, |
| const X86_64Relocator& pFactory) { |
| // if symbol is dynamic or undefine or preemptible |
| if (pSym.isDyn() || pSym.isUndef() || |
| pFactory.getTarget().isSymbolPreemptible(pSym)) |
| return false; |
| return true; |
| } |
| |
| static X86_64GOTEntry& helper_GOT_init(Relocation& pReloc, |
| bool pHasRel, |
| X86_64Relocator& pParent) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| X86_64GNULDBackend& ld_backend = pParent.getTarget(); |
| assert(pParent.getSymGOTMap().lookUp(*rsym) == NULL); |
| |
| X86_64GOTEntry* got_entry = ld_backend.getGOT().create(); |
| pParent.getSymGOTMap().record(*rsym, *got_entry); |
| |
| // If we first get this GOT entry, we should initialize it. |
| if (!pHasRel) { |
| // No corresponding dynamic relocation, initialize to the symbol value. |
| got_entry->setValue(X86Relocator::SymVal); |
| } else { |
| // Initialize got_entry content and the corresponding dynamic relocation. |
| if (helper_use_relative_reloc(*rsym, pParent)) { |
| Relocation& rel_entry = helper_DynRel_init( |
| rsym, *got_entry, 0x0, llvm::ELF::R_X86_64_RELATIVE, pParent); |
| rel_entry.setAddend(X86Relocator::SymVal); |
| pParent.getRelRelMap().record(pReloc, rel_entry); |
| } else { |
| helper_DynRel_init( |
| rsym, *got_entry, 0x0, llvm::ELF::R_X86_64_GLOB_DAT, pParent); |
| } |
| got_entry->setValue(0); |
| } |
| return *got_entry; |
| } |
| |
| static Relocator::Address helper_GOT_ORG(X86_64Relocator& pParent) { |
| return pParent.getTarget().getGOT().addr(); |
| } |
| |
| static Relocator::Address helper_get_GOT_address(Relocation& pReloc, |
| X86_64Relocator& pParent) { |
| X86_64GOTEntry* got_entry = pParent.getSymGOTMap().lookUp(*pReloc.symInfo()); |
| assert(got_entry != NULL); |
| return got_entry->getOffset(); |
| } |
| |
| static Relocator::Address helper_get_PLT_address(ResolveInfo& pSym, |
| X86_64Relocator& pParent) { |
| PLTEntryBase* plt_entry = pParent.getSymPLTMap().lookUp(pSym); |
| assert(plt_entry != NULL); |
| return pParent.getTarget().getPLT().addr() + plt_entry->getOffset(); |
| } |
| |
| static PLTEntryBase& helper_PLT_init(Relocation& pReloc, |
| X86_64Relocator& pParent) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| X86_64GNULDBackend& ld_backend = pParent.getTarget(); |
| assert(pParent.getSymPLTMap().lookUp(*rsym) == NULL); |
| |
| PLTEntryBase* plt_entry = ld_backend.getPLT().create(); |
| pParent.getSymPLTMap().record(*rsym, *plt_entry); |
| |
| // initialize plt and the corresponding gotplt and dyn rel entry. |
| assert(pParent.getSymGOTPLTMap().lookUp(*rsym) == NULL && |
| "PLT entry not exist, but DynRel entry exist!"); |
| X86_64GOTEntry* gotplt_entry = ld_backend.getGOTPLT().create(); |
| pParent.getSymGOTPLTMap().record(*rsym, *gotplt_entry); |
| |
| // init the corresponding rel entry in .rel.plt |
| Relocation& rel_entry = *ld_backend.getRelPLT().create(); |
| rel_entry.setType(llvm::ELF::R_X86_64_JUMP_SLOT); |
| rel_entry.targetRef().assign(*gotplt_entry); |
| rel_entry.setSymInfo(rsym); |
| return *plt_entry; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // X86_64 Relocation Functions and Tables |
| //===----------------------------------------------------------------------===// |
| DECL_X86_64_APPLY_RELOC_FUNCS |
| |
| /// the prototype of applying function |
| typedef Relocator::Result (*X86_64ApplyFunctionType)(Relocation& pReloc, |
| X86_64Relocator& pParent); |
| |
| // the table entry of applying functions |
| struct X86_64ApplyFunctionTriple { |
| X86_64ApplyFunctionType func; |
| unsigned int type; |
| const char* name; |
| unsigned int size; |
| }; |
| |
| // declare the table of applying functions |
| static const X86_64ApplyFunctionTriple X86_64ApplyFunctions[] = { |
| DECL_X86_64_APPLY_RELOC_FUNC_PTRS}; |
| |
| //===--------------------------------------------------------------------===// |
| // X86_64Relocator |
| //===--------------------------------------------------------------------===// |
| X86_64Relocator::X86_64Relocator(X86_64GNULDBackend& pParent, |
| const LinkerConfig& pConfig) |
| : X86Relocator(pConfig), m_Target(pParent) { |
| } |
| |
| Relocator::Result X86_64Relocator::applyRelocation(Relocation& pRelocation) { |
| Relocation::Type type = pRelocation.type(); |
| |
| if (type >= sizeof(X86_64ApplyFunctions) / sizeof(X86_64ApplyFunctions[0])) { |
| return Unknown; |
| } |
| |
| // apply the relocation |
| return X86_64ApplyFunctions[type].func(pRelocation, *this); |
| } |
| |
| const char* X86_64Relocator::getName(Relocation::Type pType) const { |
| return X86_64ApplyFunctions[pType].name; |
| } |
| |
| Relocator::Size X86_64Relocator::getSize(Relocation::Type pType) const { |
| return X86_64ApplyFunctions[pType].size; |
| } |
| |
| bool X86_64Relocator::mayHaveFunctionPointerAccess( |
| const Relocation& pReloc) const { |
| bool possible_funcptr_reloc = false; |
| switch (pReloc.type()) { |
| case llvm::ELF::R_X86_64_64: |
| case llvm::ELF::R_X86_64_32: |
| case llvm::ELF::R_X86_64_32S: |
| case llvm::ELF::R_X86_64_16: |
| case llvm::ELF::R_X86_64_8: |
| case llvm::ELF::R_X86_64_GOT64: |
| case llvm::ELF::R_X86_64_GOT32: |
| case llvm::ELF::R_X86_64_GOTPCREL64: |
| case llvm::ELF::R_X86_64_GOTPCREL: |
| case llvm::ELF::R_X86_64_GOTPLT64: { |
| possible_funcptr_reloc = true; |
| break; |
| } |
| default: { |
| possible_funcptr_reloc = false; |
| break; |
| } |
| } |
| |
| if (pReloc.symInfo()->isGlobal()) { |
| return (config().codeGenType() == LinkerConfig::DynObj) && |
| ((pReloc.symInfo()->visibility() != ResolveInfo::Default) || |
| possible_funcptr_reloc); |
| } else { |
| return (config().codeGenType() == LinkerConfig::DynObj) || |
| possible_funcptr_reloc; |
| } |
| } |
| |
| void X86_64Relocator::scanLocalReloc(Relocation& pReloc, |
| IRBuilder& pBuilder, |
| Module& pModule, |
| LDSection& pSection) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| |
| switch (pReloc.type()) { |
| case llvm::ELF::R_X86_64_64: |
| // If buiding PIC object (shared library or PIC executable), |
| // a dynamic relocations with RELATIVE type to this location is needed. |
| // Reserve an entry in .rela.dyn |
| if (config().isCodeIndep()) { |
| Relocation& reloc = helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_X86_64_RELATIVE, |
| *this); |
| getRelRelMap().record(pReloc, reloc); |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| } |
| return; |
| |
| case llvm::ELF::R_X86_64_32: |
| case llvm::ELF::R_X86_64_16: |
| case llvm::ELF::R_X86_64_8: |
| case llvm::ELF::R_X86_64_32S: |
| // If buiding PIC object (shared library or PIC executable), |
| // a dynamic relocations with RELATIVE type to this location is needed. |
| // Reserve an entry in .rela.dyn |
| if (config().isCodeIndep()) { |
| Relocation& reloc = helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| pReloc.type(), |
| *this); |
| getRelRelMap().record(pReloc, reloc); |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| } |
| return; |
| |
| case llvm::ELF::R_X86_64_PC32: |
| case llvm::ELF::R_X86_64_PC16: |
| case llvm::ELF::R_X86_64_PC8: |
| return; |
| |
| case llvm::ELF::R_X86_64_GOTPCREL: |
| // Symbol needs GOT entry, reserve entry in .got |
| // return if we already create GOT for this symbol |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| |
| // If building PIC object, a dynamic relocation with |
| // type RELATIVE is needed to relocate this GOT entry. |
| if (config().isCodeIndep()) |
| helper_GOT_init(pReloc, true, *this); |
| else |
| helper_GOT_init(pReloc, false, *this); |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| |
| default: |
| fatal(diag::unsupported_relocation) << static_cast<int>(pReloc.type()) |
| << "mclinker@googlegroups.com"; |
| break; |
| } // end switch |
| } |
| |
| void X86_64Relocator::scanGlobalReloc(Relocation& pReloc, |
| IRBuilder& pBuilder, |
| Module& pModule, |
| LDSection& pSection) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| |
| switch (pReloc.type()) { |
| case llvm::ELF::R_X86_64_64: |
| case llvm::ELF::R_X86_64_32: |
| case llvm::ELF::R_X86_64_16: |
| case llvm::ELF::R_X86_64_8: |
| case llvm::ELF::R_X86_64_32S: |
| // Absolute relocation type, symbol may needs PLT entry or |
| // dynamic relocation entry |
| if (getTarget().symbolNeedsPLT(*rsym)) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)) { |
| // Symbol needs PLT entry, we need to reserve a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rela.plt. |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| |
| if (getTarget() |
| .symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & ReservePLT), true)) { |
| // symbol needs dynamic relocation entry, set up the dynrel entry |
| if (getTarget().symbolNeedsCopyReloc(pReloc, *rsym)) { |
| LDSymbol& cpy_sym = |
| defineSymbolforCopyReloc(pBuilder, *rsym, getTarget()); |
| addCopyReloc(*cpy_sym.resolveInfo(), getTarget()); |
| } else { |
| // set Rel bit and the dyn rel |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| if (llvm::ELF::R_386_32 == pReloc.type() && |
| helper_use_relative_reloc(*rsym, *this)) { |
| Relocation& reloc = helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_X86_64_RELATIVE, |
| *this); |
| getRelRelMap().record(pReloc, reloc); |
| } else { |
| Relocation& reloc = helper_DynRel_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| pReloc.type(), |
| *this); |
| getRelRelMap().record(pReloc, reloc); |
| } |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| } |
| } |
| return; |
| |
| case llvm::ELF::R_X86_64_GOTPCREL: |
| // Symbol needs GOT entry, reserve entry in .got |
| // return if we already create GOT for this symbol |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| |
| // if the symbol cannot be fully resolved at link time, then we need a |
| // dynamic relocation |
| if (!getTarget().symbolFinalValueIsKnown(*rsym)) |
| helper_GOT_init(pReloc, true, *this); |
| else |
| helper_GOT_init(pReloc, false, *this); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| |
| case llvm::ELF::R_X86_64_PLT32: |
| // A PLT entry is needed when building shared library |
| |
| // return if we already create plt for this symbol |
| if (rsym->reserved() & ReservePLT) |
| return; |
| |
| // if the symbol's value can be decided at link time, then no need plt |
| if (getTarget().symbolFinalValueIsKnown(*rsym)) |
| return; |
| |
| // if symbol is defined in the ouput file and it's not |
| // preemptible, no need plt |
| if (rsym->isDefine() && !rsym->isDyn() && |
| !getTarget().isSymbolPreemptible(*rsym)) { |
| return; |
| } |
| |
| // Symbol needs PLT entry, we need a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| return; |
| |
| case llvm::ELF::R_X86_64_PC32: |
| case llvm::ELF::R_X86_64_PC16: |
| case llvm::ELF::R_X86_64_PC8: |
| if (getTarget().symbolNeedsPLT(*rsym) && |
| LinkerConfig::DynObj != config().codeGenType()) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)) { |
| // Symbol needs PLT entry, we need a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| |
| // Only PC relative relocation against dynamic symbol needs a |
| // dynamic relocation. Only dynamic copy relocation is allowed |
| // and PC relative relocation will be resolved to the local copy. |
| // All other dynamic relocations may lead to run-time relocation |
| // overflow. |
| if (getTarget().isDynamicSymbol(*rsym) && |
| getTarget() |
| .symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & ReservePLT), false) && |
| getTarget().symbolNeedsCopyReloc(pReloc, *rsym)) { |
| LDSymbol& cpy_sym = |
| defineSymbolforCopyReloc(pBuilder, *rsym, getTarget()); |
| addCopyReloc(*cpy_sym.resolveInfo(), getTarget()); |
| } |
| return; |
| |
| default: |
| fatal(diag::unsupported_relocation) << static_cast<int>(pReloc.type()) |
| << "mclinker@googlegroups.com"; |
| break; |
| } // end switch |
| } |
| |
| uint32_t X86_64Relocator::getDebugStringOffset(Relocation& pReloc) const { |
| if (pReloc.type() != llvm::ELF::R_X86_64_32) |
| error(diag::unsupport_reloc_for_debug_string) |
| << getName(pReloc.type()) << "mclinker@googlegroups.com"; |
| |
| if (pReloc.symInfo()->type() == ResolveInfo::Section) |
| return pReloc.target(); |
| else |
| return pReloc.symInfo()->outSymbol()->fragRef()->offset() + |
| pReloc.target() + pReloc.addend(); |
| } |
| |
| void X86_64Relocator::applyDebugStringOffset(Relocation& pReloc, |
| uint32_t pOffset) { |
| pReloc.target() = pOffset; |
| } |
| |
| //------------------------------------------------// |
| // X86_64 Each relocation function implementation // |
| //------------------------------------------------// |
| // R_X86_64_NONE |
| Relocator::Result none(Relocation& pReloc, X86_64Relocator& pParent) { |
| return Relocator::OK; |
| } |
| |
| // R_X86_64_64: S + A |
| // R_X86_64_32: |
| // R_X86_64_16: |
| // R_X86_64_8 |
| Relocator::Result abs(Relocation& pReloc, X86_64Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::DWord S = pReloc.symValue(); |
| Relocation* dyn_rel = pParent.getRelRelMap().lookUp(pReloc); |
| bool has_dyn_rel = (dyn_rel != NULL); |
| |
| LDSection& target_sect = pReloc.targetRef().frag()->getParent()->getSection(); |
| // If the flag of target section is not ALLOC, we will not scan this |
| // relocation but perform static relocation. (e.g., applying .debug section) |
| if ((llvm::ELF::SHF_ALLOC & target_sect.flag()) == 0x0) { |
| pReloc.target() = S + A; |
| return Relocator::OK; |
| } |
| |
| // A local symbol may need RELA Type dynamic relocation |
| if (rsym->isLocal() && has_dyn_rel) { |
| dyn_rel->setAddend(S + A); |
| return Relocator::OK; |
| } |
| |
| // An external symbol may need PLT and dynamic relocation |
| if (!rsym->isLocal()) { |
| if (rsym->reserved() & X86Relocator::ReservePLT) { |
| S = helper_get_PLT_address(*rsym, pParent); |
| } |
| // If we generate a dynamic relocation (except R_X86_64_RELATIVE) |
| // for a place, we should not perform static relocation on it |
| // in order to keep the addend store in the place correct. |
| if (has_dyn_rel) { |
| if (llvm::ELF::R_X86_64_64 == pReloc.type() && |
| helper_use_relative_reloc(*rsym, pParent)) { |
| dyn_rel->setAddend(S + A); |
| } else { |
| dyn_rel->setAddend(A); |
| return Relocator::OK; |
| } |
| } |
| } |
| |
| // perform static relocation |
| pReloc.target() = S + A; |
| return Relocator::OK; |
| } |
| |
| // R_X86_64_32S: S + A |
| Relocator::Result signed32(Relocation& pReloc, X86_64Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::DWord S = pReloc.symValue(); |
| |
| // There should be no dynamic relocations for R_X86_64_32S. |
| if (pParent.getRelRelMap().lookUp(pReloc) != NULL) |
| return Relocator::BadReloc; |
| |
| LDSection& target_sect = pReloc.targetRef().frag()->getParent()->getSection(); |
| // If the flag of target section is not ALLOC, we will not scan this |
| // relocation but perform static relocation. (e.g., applying .debug section) |
| // An external symbol may need PLT and dynamic relocation |
| if ((llvm::ELF::SHF_ALLOC & target_sect.flag()) != 0x0 && !rsym->isLocal() && |
| rsym->reserved() & X86Relocator::ReservePLT) |
| S = helper_get_PLT_address(*rsym, pParent); |
| |
| #if notyet |
| // Check 32-bit signed overflow. |
| Relocator::SWord V = S + A; |
| if (V > INT64_C(0x7fffffff) || V < INT64_C(-0x80000000)) |
| return Relocator::Overflow; |
| #endif |
| |
| // perform static relocation |
| pReloc.target() = S + A; |
| return Relocator::OK; |
| } |
| |
| // R_X86_64_GOTPCREL: GOT(S) + GOT_ORG + A - P |
| Relocator::Result gotpcrel(Relocation& pReloc, X86_64Relocator& pParent) { |
| if (!(pReloc.symInfo()->reserved() & X86Relocator::ReserveGOT)) { |
| return Relocator::BadReloc; |
| } |
| |
| // set symbol value of the got entry if needed |
| X86_64GOTEntry* got_entry = pParent.getSymGOTMap().lookUp(*pReloc.symInfo()); |
| if (X86Relocator::SymVal == got_entry->getValue()) |
| got_entry->setValue(pReloc.symValue()); |
| |
| // setup relocation addend if needed |
| Relocation* dyn_rel = pParent.getRelRelMap().lookUp(pReloc); |
| if ((dyn_rel != NULL) && (X86Relocator::SymVal == dyn_rel->addend())) { |
| dyn_rel->setAddend(pReloc.symValue()); |
| } |
| |
| Relocator::Address GOT_S = helper_get_GOT_address(pReloc, pParent); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::Address GOT_ORG = helper_GOT_ORG(pParent); |
| // Apply relocation. |
| pReloc.target() = GOT_S + GOT_ORG + A - pReloc.place(); |
| return Relocator::OK; |
| } |
| |
| // R_X86_64_PLT32: PLT(S) + A - P |
| Relocator::Result plt32(Relocation& pReloc, X86_64Relocator& pParent) { |
| // PLT_S depends on if there is a PLT entry. |
| Relocator::Address PLT_S; |
| if ((pReloc.symInfo()->reserved() & X86Relocator::ReservePLT)) |
| PLT_S = helper_get_PLT_address(*pReloc.symInfo(), pParent); |
| else |
| PLT_S = pReloc.symValue(); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::Address P = pReloc.place(); |
| pReloc.target() = PLT_S + A - P; |
| return Relocator::OK; |
| } |
| |
| // R_X86_64_PC32: S + A - P |
| // R_X86_64_PC16 |
| // R_X86_64_PC8 |
| Relocator::Result rel(Relocation& pReloc, X86_64Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::DWord S = pReloc.symValue(); |
| Relocator::DWord P = pReloc.place(); |
| |
| LDSection& target_sect = pReloc.targetRef().frag()->getParent()->getSection(); |
| // If the flag of target section is not ALLOC, we will not scan this |
| // relocation but perform static relocation. (e.g., applying .debug section) |
| if ((llvm::ELF::SHF_ALLOC & target_sect.flag()) == 0x0) { |
| pReloc.target() = S + A - P; |
| return Relocator::OK; |
| } |
| |
| // setup relocation addend if needed |
| Relocation* dyn_rel = pParent.getRelRelMap().lookUp(pReloc); |
| if ((dyn_rel != NULL) && (X86Relocator::SymVal == dyn_rel->addend())) { |
| dyn_rel->setAddend(S); |
| } |
| |
| // An external symbol may need PLT and dynamic relocation |
| if (!rsym->isLocal()) { |
| if (rsym->reserved() & X86Relocator::ReservePLT) { |
| S = helper_get_PLT_address(*rsym, pParent); |
| } |
| if (pParent.getTarget() |
| .symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & X86Relocator::ReservePLT), false)) { |
| return Relocator::Overflow; |
| } |
| } |
| |
| // perform static relocation |
| pReloc.target() = S + A - P; |
| return Relocator::OK; |
| } |
| |
| Relocator::Result unsupported(Relocation& pReloc, X86_64Relocator& pParent) { |
| return Relocator::Unsupported; |
| } |
| |
| } // namespace mcld |
